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Hepatic Encephalopathy in Chronic Liver Disease 2014 Practice Guideline by the American Associationfor the Study of Liver Diseases and the EuropeanAssociation for the Study of the Live

Hepatic Encephalopathy in Chronic Liver Disease:
2014 Practice Guideline by the American Association
for the Study of Liver Diseases and the European
Association for the Study of the Liver
Hendrik Vilstrup,1 Piero Amodio,2 Jasmohan Bajaj,3,4 Juan Cordoba,5† Peter Ferenci,6 Kevin D. Mullen,7
Karin Weissenborn,8 and Philip Wong9
The AASLD/EASL Practice Guideline Subcommittee
on Hepatic Encephalopathy are: Jayant A. Talwalkar
(Chair, AASLD), Hari S. Conjeevaram, Michael Porayko,
Raphael B. Merriman, Peter L.M. Jansen, and Fabien
Zoulim. This guideline has been approved by the American Association for the Study of Liver Diseases and the
European Association for the Study of the Liver and represents the position of both associations.
These recommendations provide a data-supported
approach. They are based on the following: (1) formal
review and analysis of the recently published world literature on the topic; (2) guideline policies covered by
the American Association for the Study of Liver Diseases/European Association for the Study of the Liver
(AASLD/EASL) Policy on the Joint Development and
Use of Practice Guidelines; and (3) the experience of
the authors in the specified topic.
Intended for use by physicians, these recommendations suggest preferred approaches to the diagnostic,
therapeutic, and preventive aspects of care. They are
intended to be flexible, in contrast to standards of
care, which are inflexible policies to be followed in
every case. Specific recommendations are based on relevant published information.
To more fully characterize the available evidence
supporting the recommendations, the AASLD/EASL
Practice Guidelines Subcommittee has adopted the
classification used by the Grading of Recommendation
Assessment, Development, and Evaluation (GRADE)
workgroup, with minor modifications (Table 1). The
classifications and recommendations are based on three
categories: the source of evidence in levels I through
III; the quality of evidence designated by high (A),
moderate (B), or low quality (C); and the strength of
recommendations classified as strong (1) or weak (2).
Literature Review and Analysis
The literature databases and search strategies are outlined below. The resulting literature database was available
to all members of the writing group (i.e., the authors).
Abbreviations: AASLD, American Association for the Study of Liver Diseases; ACLF, acute-on-chronic liver failure; ALD, alcoholic liver disease; ALF, acute liver
failure; BCAAs, branced-chain amino acids; CFF, Critical Flicker Frequency; CHE, covert HE; CLD, chronic liver disease; CRT, Continuous Reaction Time; CT,
computed tomography; DM, diabetes mellitus; EASL, European Association for the Study of the Liver; EEG, electroencephalography; GI, gastrointestinal; GRADE,
the Grading of Recommendation Assessment, Development, and Evaluation; GCS, Glasgow Coma Scale; GPB, glyceryl phenylbutyrate; HCV, hepatitis C virus;
HE, hepatic encephalopathy; HM, hepatic myelopathy; ICT, Inhibitory Control Test; ISHEN, International Society for Hepatic Encephalopathy and Nitrogen
Metabolism; IV, intravenous; LOLA, L-ornithine L-aspartate; LT, Liver transplantation; MHE, minimal HE; MR, magnetic resonance; OHE, overt HE; PH, portal hypertension; PHES, Psychometric Hepatic Encephalopathy Score; PP, portal pressure; PSE, portosystemic encephalopathy; PSS, portosystemic shunting; RCT,
randomized, controlled trial; TIPS, transjugular intrahepatic portosystemic shunt; VB, variceal bleeding; WHC, West Haven Criteria; WM, working memory.
From the 1Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; 2Department of Medicine - DIMED, University of
Padova, Padova, Italy; 3Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA; 4McGuire Veterans Affairs
Medical Center, Richmond, VA; 5Liver Unit, Hospital Vall d’Hebron, Barcelona, Spain; 6Department of Internal Medicine III (Gastroenterology and Hepatology),
Medical University of Vienna, Vienna General Hospital (AKH), Vienna, Austria; 7Division of Gastroenterology, MetroHealth Medical Center, Case Western
Reserve University, Cleveland, OH; 8Department of Neurology, Hannover Medical School, Hannover, Germany; 9Division of Gastroenterology and Hepatology,
McGill University, Montreal, Quebec, Canada.
All AASLD Practice Guidelines are updated annually. If you are viewing a Practice Guideline that is more than 12 months old, please visit for
an update in the material.
This Practice Guideline is copublished in the Journal of Hepatology.
Received April 28, 2014; accepted April 28, 2014.
HEPATOLOGY, August 2014
Table 1. GRADE System for Evidence
Randomized, controlled trials
Controlled trials without randomization
Cohort or case-control analytic studies
Multiple time series, dramatic uncontrolled experiments
Opinions of respected authorities, descriptive epidemiology
High quality
Low quality
Further research is very unlikely to change our confidence in the estimated effect.
Further research is likely to have an important impact on our confidence in the estimate effect and may change the
Further research is likely to have an important impact on our confidence in the estimate effect and is likely to change
the estimate. Any change of estimate is uncertain.
Factors influencing the strength of recommendation included the quality of evidence, presumed patient-important outcomes, and costs.
Variability in preferences and values, or more uncertainty. Recommendation is made with less certainty, higher costs, or
resource consumption.
They selected references within their field of expertise
and experience and graded the references according to
the GRADE system.1 The selection of references for the
guideline was based on a validation of the appropriateness
of the study design for the stated purpose, a relevant
number of patients under study, and confidence in the
participating centers and authors. References on original
data were preferred and those that were found unsatisfactory in any of these respects were excluded from further
evaluation. There may be limitations in this approach
when recommendations are needed on rare problems or
problems on which scant original data are available. In
such cases, it may be necessary to rely on less-qualified
references with a low grading. As a result of the important changes in the treatment of complications of cirrhosis (renal failure, infections, and variceal bleeding [VB]),
studies performed more than 30 years ago have generally
not been considered for these guidelines.
Hepatic encephalopathy (HE) is a frequent complication and one of the most debilitating manifestations
of liver disease, severely affecting the lives of patients
and their caregivers. Furthermore, cognitive impairment associated with cirrhosis results in utilization of
more health care resources in adults than other manifestations of liver disease.2 Progress in the area has
been hindered by the complex pathogenesis that is not
yet fully elucidated. Apart from such biological factors,
there remains the larger obstacle that there are no universally accepted standards for the definition, diagnosis, classification, or treatment of HE, mostly as a
result of insufficient clinical studies and standardized
definitions. Clinical management tends to be dependent on local standards and personal views. This is an
unfavorable situation for patients and contrasts with
the severity of the condition and the high level of
standardization in other complications of cirrhosis.
The lack of consistency in the nomenclature and general standards renders comparisons among studies and
patient populations difficult, introduces bias, and hinders progress in clinical research for HE. The latest
attempts to standardize the nomenclature were published in 2002 and suggestions for the design of HE
trials in 2011. Because there is an unmet need for
Address reprint requests to: Hendrik Vilstrup, M.D., D.Sc., Department of Hepatology and Gastroenterology, Aarhus University Hospital, 44 Nørrebrogade, DK
8000 Aarhus C, Denmark. E-mail: [email protected]; fax: 145 7846 2860.
C 2014 by the American Association for the Study of Liver Diseases.
Copyright V
View this article online at
DOI 10.1002/hep.27210
Potential conflict of interest: Dr. Wong consults, advises, and received grants from Gilead. He consults and advises Roche. He advises and received grants from
Vertex. Dr. Ferenci advises Ocera and Salix. Dr. Bajaj consults and received grants from Otsuka and Grifols. He consults for Salix. Dr. Mullen is on the speakers’
bureau for Salix and Abbott.
HEPATOLOGY, Vol. 60, No. 2, 2014
recommendations on the clinical management of HE,
the EASL and the AASLD jointly agreed to create
these practice guidelines. It is beyond the scope of
these guidelines to elaborate on the theories of pathogenesis of HE, as well as the management of encephalopathy resulting from acute liver failure (ALF), which
has been published as guidelines recently. Rather, its
aim is to present standardized terminology and recommendations to all health care workers who have
patients with HE, regardless of their medical discipline, and focus on adult patients with chronic liver
disease (CLD), which is, by far, the most frequent
As these guidelines on HE were created, the authors
found a limited amount of high-quality evidence to
extract from the existing literature. There are many reasons for this; the elusive character of HE is among
them, as well as the lack of generally accepted and utilized terms for description and categorization of HE.
This makes a practice guideline all the more necessary
for future improvement of clinical studies and, subsequently, the quality of management of patients with
HE. With the existing body of evidence, these guidelines encompass the authors’ best, carefully considered
opinions. Although not all readers may necessarily agree
with all aspects of the guidelines, their creation and
adherence to them is the best way forward, with future
adjustments when there is emergence of new evidence.
Definition of the Disease/Condition
Advanced liver disease and portosystemic shunting
(PSS), far from being an isolated disorder of the liver,
have well-known consequences on the body and, notably, on brain functioning. The alterations of brain
functioning, which can produce behavioral, cognitive,
and motor effects, were termed portosystemic encephalopathy (PSE)3 and later included in the term
Unless the underlying liver disease is successfully
treated, HE is associated with poor survival and a high
risk of recurrence.5,6 Even in its mildest form, HE
reduces health-related quality of life and is a risk factor
for bouts of severe HE.7-9
Definition of HE
Hepatic encephalopathy is a brain dysfunction caused
by liver insufficiency and/or PSS; it manifests as a wide
spectrum of neurological or psychiatric abnormalities
ranging from subclinical alterations to coma.
This definition, in line with previous versions,10,11
is based on the concept that encephalopathies are
“diffuse disturbances of brain function”5 and that the
adjective “hepatic” implies a causal connection to liver
insufficiency and/or perihepatic vascular shunting.6
The incidence and prevalence of HE are related to
the severity of the underlying liver insufficiency and
PSS.12-15 In patients with cirrhosis, fully symptomatic
overt HE (OHE) is an event that defines the decompensated phase of the disease, such as VB or ascites.7
Overt hepatic encephalopathy is also reported in subjects without cirrhosis with extensive PSS.8,9
The manifestation of HE may not be an obvious
clinical finding and there are multiple tools used for
its detection, which influences the variation in the
reported incidence and prevalence rates.
The prevalence of OHE at the time of diagnosis of
cirrhosis is 10%-14% in general,16-18 16%-21% in
those with decompensated cirrhosis,7,19 and 10%-50%
in patients with transjugular intrahepatic portosystemic
shunt (TIPS).20,21 The cumulated numbers indicate
that OHE will occur in 30%-40% of those with cirrhosis at some time during their clinical course and in
the survivors in most cases repeatedly.22 Minimal HE
(MHE) or covert HE (CHE) occurs in 20%-80% of
patients with cirrhosis.23-27,81 The prevalence of HE in
prehepatic noncirrhotic portal hypertension (PH) is
not well defined.
The risk for the first bout of OHE is 5%-25%
within 5 years after cirrhosis diagnosis, depending on
the presence of risk factors, such as other complications to cirrhosis (MHE or CHE, infections, VB, or
ascites) and probably diabetes and hepatitis C.28-32
Subjects with a previous bout of OHE were found to
have a 40% cumulative risk of recurring OHE at 1
year,33 and subjects with recurrent OHE have a 40%
cumulative risk of another recurrence within 6
months, despite lactulose treatment. Even individuals
with cirrhosis and only mild cognitive dysfunction or
mild electroencephalography (EEG) slowing develop
approximately one bout of OHE per 3 years of
After TIPS, the median cumulative 1-year incidence
of OHE is 10%-50%36,37 and is greatly influenced by
the patient selection criteria adopted.38 Comparable
data were obtained by PSS surgery.39
It gives an idea of the frequent confrontation of the
health care system by patients with HE that they
accounted for approximately 110,000 hospitalizations
yearly (2005-2009)40 in the United States. Though
numbers in the European Union (EU) are not readily
available, these predictions are expected to be similar.
Furthermore, the burden of CLD and cirrhosis is rapidly increasing,41,42 and more cases will likely be
encountered to further define the epidemiology of HE.
Clinical Presentation
Hepatic encephalopathy produces a wide spectrum of
nonspecific neurological and psychiatric manifestations.10
In its lowest expression,43,44 HE alters only psychometric
tests oriented toward attention, working memory (WM),
psychomotor speed, and visuospatial ability, as well as electrophysiological and other functional brain measures.45,46
As HE progresses, personality changes, such as apathy,
irritability, and disinhibition, may be reported by the
patient’s relatives,47 and obvious alterations in consciousness and motor function occur. Disturbances of the sleepwake cycle with excessive daytime sleepiness are frequent,48 whereas complete reversal of the sleep-wake cycle
is less consistently observed.49,50 Patients may develop
progressive disorientation to time and space, inappropriate behavior, and acute confusional state with agitation or
somnolence, stupor, and, finally, coma.51 The recent
ISHEN (International Society for Hepatic Encephalopathy and Nitrogen Metabolism) consensus uses the onset
of disorientation or asterixis as the onset of OHE.65
In noncomatose patients with HE, motor system
abnormalities, such as hypertonia, hyper-reflexia, and a
positive Babinski sign, can be observed. In contrast,
deep tendon reflexes may diminish and even disappear
in coma,52 although pyramidal signs can still be
observed. Rarely, transient focal neurological deficits can
occur.53 Seizures are very rarely reported in HE.54-56
Extrapyramidal dysfunction, such as hypomimia, muscular rigidity, bradykinesia, hypokinesia, monotony and
slowness of speech, parkinsonian-like tremor, and dyskinesia with diminished voluntary movements, are common
findings; in contrast, the presence of involuntary movements similar to tics or chorea occur rarely.52,57
Asterixis or “flapping tremor” is often present in the
early to middle stages of HE that precede stupor or
coma and is, in actuality, not a tremor, but a negative
myoclonus consisting of loss of postural tone. It is easily elicited by actions that require postural tone, such
as hyperextension of the wrists with separated fingers
or the rhythmic squeezing of the examiner’s fingers.
However, asterixis can be observed in other areas, such
as the feet, legs, arms, tongue, and eyelids. Asterixis is
not pathognomonic of HE because it can be observed
in other diseases57 (e.g., uremia).
HEPATOLOGY, August 2014
Notably, the mental (either cognitive or behavioral)
and motor signs of HE may not be expressed, or do
not progress in parallel, in each individual, therefore
producing difficulties in staging the severity of HE.
Hepatic myelopathy (HM)58 is a particular pattern
of HE possibly related to marked, long-standing portocaval shunting, characterized by severe motor abnormalities exceeding the mental dysfunction. Cases of
paraplegia with progressive spasticity and weakness of
lower limbs with hyper-reflexia and relatively mild persistent or recurrent mental alterations have been
reported and do not respond to standard therapy,
including ammonia lowering, but may reverse with
liver transplantation (LT).59
Persistent HE may present with prominent extrapyramidal and/or pyramidal signs, partially overlapping
with HM, in which postmortem brain examination
reveals brain atrophy.60 This condition was previously
called acquired hepatolenticular degeneration, a term
currently considered obsolete. However, this cirrhosisassociated parkinsonism is unresponsive to ammonialowering therapy and may be more common than
originally thought in patients with advanced liver disease, presenting in approximately 4% of cases.61
Apart from these less-usual manifestations of HE, it
is widely accepted in clinical practice that all forms of
HE and their manifestations are completely reversible,
and this assumption still is a well-founded operational
basis for treatment strategies. However, research on
liver-transplanted HE patients and on patients after
resolution of repeated bouts of OHE casts doubt on
the full reversibility. Some mental deficits, apart from
those ascribable to other transplantation-related causes,
may persist and are mentioned later under transplantation.135 Likewise, episodes of OHE may be associated
with persistent cumulative deficits in WM and
Hepatic encephalopathy should be classified according to all of the following four factors.10
1. According to the underlying disease, HE is subdivided into
Type A resulting from ALF
Type B resulting predominantly from portosystemic bypass or shunting
Type C resulting from cirrhosis
The clinical manifestations of types B and C are similar, whereas type A has distinct features and, notably,
HEPATOLOGY, Vol. 60, No. 2, 2014
Table 2. WHC and Clinical Description
WHC Including
Suggested Operative Criteria
No encephalopathy at all, no history of HE
Tested and proved to be normal
Psychometric or neuropsychological
alterations of tests exploring psychomotor
speed/executive functions or neurophysiological alterations without clinical evidence
of mental change
Abnormal results of established psychometric or
neuropsychological tests without clinical
No universal criteria for diagnosis
Local standards and expertise
Trivial lack of awareness
Euphoria or anxiety
Shortened attention span
Impairment of addition or subtraction
Altered sleep rhythm
Despite oriented in time and space (see
below), the patient appears to have some cognitive/behavioral decay with respect to his or
her standard on clinical examination or to the
Clinical findings usually not
Grade I
Lethargy or apathy
Disorientation for time
Obvious personality change
Inappropriate behavior
Disoriented for time (at least three of the followings are wrong: day of the month, day of the
week, month, season, or year) 6 the other
mentioned symptoms
Clinical findings variable, but
reproducible to some extent
Grade II
Somnolence to semistupor
Responsive to stimuli
Gross disorientation
Bizarre behavior
Disoriented also for space (at least three of the
following wrongly reported: country, state [or
region], city, or place) 6 the other mentioned
Clinical findings reproducible to
some extent
Does not respond even to painful stimuli
Comatose state usually
Grade III
Grade IV
All conditions are required to be related to liver insufficiency and/or PSS.
may be associated with increased intracranial pressure
and a risk of cerebral herniation. The management of
HE type A is described in recent guidelines on
ALF62,63 and is not included in this document.
2. According to the severity of manifestations. The
continuum that is HE has been arbitrarily subdivided. For clinical and research purposes, a scheme
of such grading is provided (Table 2). Operative
classifications that refer to defined functional
impairments aim at increasing intra- and inter-rater
reliability and should be used whenever possible.
nearly all bouts of episodic HE type C and should be
actively sought and treated when found (Table 3).
A fifth classification, according to whether or not
the patient has acute-on-chronic liver failure (ACLF),
has recently been suggested.64 Although the management, mechanism, and prognostic impact differ, this
classification is still a research area.
Differential Diagnoses
The diagnosis requires the detection of signs suggestive of HE in a patient with severe liver insufficiency
3. According to its time course, HE is subdivided into
Episodic HE
Recurrent HE denotes bouts of HE that occur
with a time interval of 6 months or less.
Persistent HE denotes a pattern of behavioral
alterations that are always present and interspersed with relapses of overt HE.
4. According to the existence of precipitating factors,
HE is subdivided into
Nonprecipitated or
Precipitated, and the precipitating factors should be
specified. Precipitating factors can be identified in
Table 3. Precipitating Factors for OHE
by Decreasing Frequency
GI bleeding
Diuretic overdose
Electrolyte disorder
Electrolyte disorder
Diuretic overdose
GI bleeding
Modified from Strauss E, da Costa MF. The importance of bacterial infections
as precipitating factors of chronic hepatic encephalopathy in cirrhosis. Hepatogastroenterology 1998;45:900-904.
*More recent unpublished case series confirm the dominant role of
Table 4. Differential Diagnosis of HE
Overt HE or acute confusional state
Diabetic (hypoglycemia, ketoacidosis, hyperosmolar, lactate acidosis)
Alcohol (intoxication, withdrawal, Wernicke)
Drugs (benzodiazepines, neuroleptics, opioids)
Electrolyte disorders (hyponatremia and hypercalcemia)
Nonconvulsive epilepsy
Psychiatric disorders
Intracranial bleeding and stroke
Severe medical stress (organ failure and inflammation)
Other presentations
Dementia (primary and secondary)
Brain lesions (traumatic, neoplasms, normal pressure hydrocephalus)
Obstructive sleep apnea
Hyponatremia and sepsis can both produce encephalopathy per se and precipitate HE by interactions with the pathophysiological mechanisms. In endstage liver disease, uremic encephalopathy and HE may overlap.
and/or PSS who does not have obvious alternative
causes of brain dysfunction. The recognition of precipitating factors for HE (e.g., infection, bleeding, and
constipation) supports the diagnosis of HE. The differential diagnosis should consider common disorders
altering the level of consciousness (Table 4).
1. Hepatic encephalopathy should be classified
according to the type of underlying disease, severity of
manifestations, time course, and precipitating factors
(GRADE III, A, 1).
2. A diagnostic workup is required, considering
other disorders that can alter brain function and
mimic HE (GRADE II-2, A, 1).
Every case and bout of HE should be described and classified according to all four factors, and this should be
repeated at relevant intervals according to the clinical situation. The recommendations are summarized in Table 5.
Diagnosis and Testing
Clinical Evaluation
Judging and measuring the severity of HE is
approached as a continuum.65 The testing strategies in
place range from simple clinical scales to sophisticated
psychometric and neurophysiological tools; however,
none of the current tests are valid for the entire spectrum.11,66 The appropriate testing and diagnostic
options differ according to the acuity of the presentation and the degree of impairment.67
Diagnosis and Testing for OHE
The diagnosis of OHE is based on a clinical examination and a clinical decision. Clinical scales are used
HEPATOLOGY, August 2014
to analyze its severity. Specific quantitative tests are
only needed in study settings. The gold standard is the
West Haven criteria (WHC; Table 2, including clinical
description). However, they are subjective tools with
limited interobserver reliability, especially for grade I
HE, because slight hypokinesia, psychomotor slowing,
and a lack of attention can easily be overlooked in
clinical examination. In contrast, the detection of disorientation and asterixis has good inter-rater reliability
and thus are chosen as marker symptoms of OHE.67
Orientation or mixed scales have been used to distinguish the severity of HE.68,69 In patients with significantly altered consciousness, the Glasgow Coma Scale
(GCS; Table 6) is widely employed and supplies an
operative, robust description.
Diagnosing cognitive dysfunction is not difficult. It
can be established from clinical observation as well as
neuropsychological or neurophysiological tests. The
difficulty is to assign them to HE. For this reason,
OHE still remains a diagnosis of exclusion in this
patient population that is often susceptible to mental
status abnormalities resulting from medications, alcohol abuse, drug use, effects of hyponatremia, and psychiatric disease (Table 4). Therefore, as clinically
indicated, exclusion of other etiologies by laboratory
and radiological assessment for a patient with altered
mental status in HE is warranted.
Testing for MHE and CHE
Minimal hepatic encephalopathy and CHE is
defined as the presence of test-dependent or clinical
signs of brain dysfunction in patients with CLD who
are not disoriented or display asterixis. The term
“minimal” conveys that there is no clinical sign, cognitive or other, of HE. The term “covert” includes minimal and grade 1 HE. Testing strategies can be divided
into two major types: psychometric and neurophysiological.70,71 Because the condition affects several
Table 5. HE Description and Clinical Example
Time Course
Spontaneous or
Precipitated (specify)
The HE patient should be characterized by one component from each of the
four columns. Example of a recommended description of a patient with HE:
“The patient has HE, Type C, Grade 3, Recurrent, Precipitated (by urinary tract
infection).” The description may be supplemented with operative classifications
(e.g., the Glasgow Coma Score or psychometric performance).
HEPATOLOGY, Vol. 60, No. 2, 2014
Table 6. GCS169
Does not open eyes
Opens eyes in response to
painful stimuli
Opens eyes in response
to voice
Opens eyes spontaneously
Makes no sounds
Incomprehensible sounds
Utters inappropriate words
Confused, disoriented
Oriented, converses
Makes no movements
Extension to painful stimuli
(decerebrate response)
Abnormal flexion to painful
stimuli (decorticate response)
to painful stimuli
Localizes painful
The scale comprises three tests: eyes, verbal, and motor responses. The three values separately as well as their sum are considered. The lowest possible GCS
(the sum) is 3 (deep coma or death), whereas the highest is 15 (fully awake person).
Abbreviation: N/A, not applicable.
components of cognitive functioning, which may not
be impaired to the same degree, the ISHEN suggests
the use of at least two tests, depending on the local
population norms and availability, and preferably with
one of the tests being more widely accepted so as to
serve as a comparator.
Testing for MHE and CHE is important because it
can prognosticate OHE development, indicate poor
quality of life and reduced socioeconomic potential,
and help counsel patients and caregivers about the disease. The occurrence of MHE and CHE in patients
with CLD seems to be as high as 50%,72 so, ideally,
every patient at risk should be tested. However, this
strategy may be costly,73 and the consequences of the
screening procedure are not always clear and treatment
is not always recommended. An operational approach
may be to test patients who have problems with their
quality of life or in whom there are complaints from
the patients and their relatives.74 Tests positive for
MHE or CHE before stopping HE drug therapy will
identify patients at risk for recurrent HE.33,75 Furthermore, none of the available tests are specific for the
condition,76 and it is important to test only patients
who do not have confounding factors, such as neuropsychiatric disorders, psychoactive medication, or current alcohol use.
Testing should be done by a trained examiner
adhering to scripts that accompany the testing tools. If
the test result is normal (i.e., negative for MHE or
CHE), repeat testing in 6 months has been recommended.77 A diagnosis of MHE or CHE does not
automatically mean that the affected subject is a dangerous driver.78 Medical providers are not trained to
formally evaluate fitness to drive and are also not legal
representatives. Therefore, providers should act in the
best interests of both the patient and society while following the applicable local laws.78 However, doctors
cannot evade the responsibility of counseling patients
with diagnosed HE on the possible dangerous conse-
quences of their driving, and, often, the safest advice is
to stop driving until the responsible driving authorities
have formally cleared the patient for safe driving. In
difficult cases, the doctor should consult with the
authorities that have the expertise to test driving ability
and the authority to revoke the license.
A listing of the most established testing strategies is
given below. The test recommendation varies depending on the logistics, availability of tests, local norms,
and cost.65,66,71
1. Portosystemic encephalopathy (PSE) syndrome test.
This test battery consists of five paper-pencil tests
that evaluate cognitive and psychomotor processing
speed and visuomotor coordination. The tests are
relatively easy to administer and have good external
validity.76 The test is often referred to as the Psychometric Hepatic Encephalopathy Score (PHES),
with the latter being the sum score from all subtests of the battery. It can be obtained from Hannover Medical School (Hannover, Germany), which
holds the copyright ([email protected]). The test was developed in Germany and
has been translated for use in many other countries.
For illiterate patients, the figure connection test has
been used as a subtest instead of the number connection test.79
2. The Critical Flicker Frequency (CFF) test is a psychophysiological tool defined as the frequency at which a
fused light (presented from 60 Hz downward) appears
to be flickering to the observer. Studies have shown its
reduction with worsening cognition and improvement after therapy. The CFF test requires several trials, intact binocular vision, absence of red-green
blindness, and specialized equipment.80,81
3. The Continuous Reaction Time (CRT) test. The
CRT test relies on repeated registration of the
motor reaction time (pressing a button) to auditory
stimuli (through headphones). The most important
test result is the CRT index, which measures the
stability of the reaction times. The test result can
differentiate between organic and metabolic brain
impairment and is not influenced by the patient’s
age or gender, and there is no learning or tiring
effect. Simple software and hardware are required.82
The Inhibitory Control Test (ICT) is a computerized test of response inhibition and working memory83 and is freely downloadable at
The ICT test has been judged to have good validity, but requires highly functional patients. The
norms for the test have to be elaborated beyond
the few centers that have used it.
The Stroop test evaluates psychomotor speed and
cognitive flexibility by the interference between recognition reaction time to a colored field and a written
color name. Recently, mobile application software
(“apps” for a smartphone or tablet computer) based
on the test has been shown to identify cognitive dysfunction in cirrhosis compared to paper-pencil
tests.84 Further studies are under way to evaluate its
potential for screening for MHE and CHE.
The SCAN Test is a computerized test that measures
speed and accuracy to perform a digit recognition
memory task of increasing complexity. The SCAN
Test has been shown to be of prognostic value.85
Electroencephalography examination can detect
changes in cortical cerebral activity across the spectrum of HE without patient cooperation or risk of
a learning effect.70 However, it is nonspecific and
may be influenced by accompanying metabolic disturbances, such as hyponatremia as well as drugs.
Possibly, the reliability of EEG analysis can increase
with quantitative analysis. This specifically should
include the background frequency with mean dominant frequency or spectral band analysis.60 Also, in
most situations, EEG requires an institutional setup
and neurological expertise in evaluation, and the
cost varies among hospitals.
Although the above-described tests have been used
to test for MHE and CHE, there is, most often, a
poor correlation between them because HE is a multidimensional dysfunction.86 Learning effect is often
observed with psychometric tests and it is unclear
whether current HE therapy plays a role in the test
performance. Therefore, interpretation of these tests
and consideration of the results for further management need an understanding of the patient’s history,
current therapy, and effect on the patient’s daily activities, if signs of HE are found. For multicenter studies,
the diagnosis of MHE or CHE by consensus should
HEPATOLOGY, August 2014
utilize at least two of the current validated testing
strategies: paper-pencil (PHES) and one of the following: computerized (CRT, ICT, SCAN, or Stroop) or
neurophysiological (CFF or EEG).66 In the clinical
routine or single-center studies, investigators may use
tests for assessing the severity of HE with which they
are familiar, provided that normative reference data are
available and the tests have been validated for use in
this patient population.66
Laboratory Testing
High blood-ammonia levels alone do not add any
diagnostic, staging, or prognostic value in HE patients
with CLD.87 However, in case an ammonia level is
checked in a patient with OHE and it is normal, the
diagnosis of HE is in question. For ammonia-lowering
drugs, repeated measurements of ammonia may be
helpful to test the efficacy. There may be logistic challenges to accurately measure blood ammonia, which
should be taken into consideration. Ammonia is
reported either in venous, arterial blood, or plasma
ammonia, so the relevant normal should be used. Multiple methods are available, but measurements should
only be employed when laboratory standards allow for
reliable analyses.
Brain Scans
Computed tomography (CT) or magnetic resonance
(MR) or other image modality scans do not contribute
diagnostic or grading information. However, the risk
of intracerebral hemorrhage is at least 5-fold increased
in this patient group,88 and the symptoms may be
indistinguishable, so a brain scan is usually part of the
diagnostic workup of first-time HE and on clinical
suspicion of other pathology.
3. Hepatic encephalopathy should be treated as a
continuum ranging from unimpaired cognitive function with intact consciousness through coma
(GRADE III, A, 1).
4. The diagnosis of HE is through exclusion of other
causes of brain dysfunction (GRADE II-2, A, 1).
5. Hepatic encephalopathy should be divided into
various stages of severity, reflecting the degree of selfsufficiency and the need for care (GRADE III, B, 1).
6. Overt hepatic encephalopathy is diagnosed by
clinical criteria and can be graded according the
WHC and the GCS (GRADE II-2, B, 1).
7. The diagnosis and grading of MHE and CHE
can be made using several neurophysiological and
HEPATOLOGY, Vol. 60, No. 2, 2014
psychometric tests that should be performed by experienced examiners (GRADE II-2, B, 1).
8. Testing for MHE and CHE could be used in
patients who would most benefit from testing, such as
those with impaired quality of life or implication on
employment or public safety (GRADE III, B, 2).
9. Increased blood ammonia alone does not add
any diagnostic, staging, or prognostic value for HE
in patients with CLD. A normal value calls for diagnostic reevaluation (GRADE II-3, A, 1).
General Principles
At this time, only OHE is routinely treated.10 Minimal hepatic encephalopathy and CHE, as its title
implies, is not obvious on routine clinical examination
and is predominantly diagnosed by techniques outlined in the previous section. Despite its subtle nature,
MHE and CHE can have a significant effect on a
patient’s daily living. Special circumstances can prevail
where there may be an indication to treat such a
patient (e.g., impairment in driving skills, work performance, quality of life, or cognitive complaints).
Liver transplantation is mentioned under the treatment
General recommendations for treatment of episodic
OHE type C include the following:
10. An episode of OHE (whether spontaneous or precipitated) should be actively treated (GRADE II-2, A, 1).
11. Secondary prophylaxis after an episode for
overt HE is recommended (GRADE I, A, 1).
12. Primary prophylaxis for prevention of episodes of
OHE is not required, except in patients with cirrhosis with
a known high risk to develop HE (GRADE II-3, C, 2).
13. Recurrent intractable OHE, together with
liver failure, is an indication for LT (GRADE I).
Specific Approach to OHE Treatment
A four-pronged approach to management of HE is
recommended (GRADE II-2, A, 1):
14. Initiation of care for patients with altered
15. Alternative causes of altered mental status
should be sought and treated.
16. Identification of precipitating factors and
their correction
17. Commencement of empirical HE treatment
Comments on Management Strategy
Patients with higher grades of HE who are at risk
or unable to protect their airway need more intensive
monitoring and are ideally managed in an intensive
care setting. Alternative causes of encephalopathy are
not infrequent in patients with advanced cirrhosis.
Technically, if other causes of encephalopathy are present, then the episode of encephalopathy may not be
termed HE. In the clinical setting, what transpires is
treatment of both HE and non-HE.
Controlling precipitating factors in the management
of OHE is of paramount importance, because nearly
90% of patients can be treated with just correction of
the precipitating factor.89 Careful attention to this
issue is still the cornerstone of HE management.
Therapy for Episodes of OHE
In addition to the other elements of the fourpronged approach to treatment of HE, specific drug
treatment is part of the management. Most drugs have
not been tested by rigorous randomized, controlled
studies and are utilized based on circumstantial observations. These agents include nonabsorbable disaccharides, such as lactulose, and antibiotics, such as
rifaximin. Other therapies, such as oral branched-chain
amino acids (BCAAs), intravenous (IV) L-ornithine Laspartate (LOLA), probiotics, and other antibiotics,
have also been used. In the hospital, a nasogastric tube
can be used to administer oral therapies in patients
who are unable to swallow or have an aspiration risk.
Nonabsorbable Disaccharides. Lactulose is generally used as initial treatment for OHE. A large metaanalysis of trial data did not completely support lactulose as a therapeutic agent for treatment of OHE, but
for technical reasons, it did not include the largest trials,
and these agents continue to be used widely.90 Lack of
effect of lactulose should prompt a clinical search for
unrecognized precipitating factors and competing causes
for the brain impairment. Though it is assumed that
the prebiotic effects (the drug being a nondigestible substance that promotes the growth of beneficial microorganisms in the intestines) and acidifying nature of
lactulose have an additional benefit beyond the laxative
effect, culture-independent studies have not borne those
out.75,91 In addition, most recent trials on lactulose
have been open label in nature. Cost considerations
alone add to the argument in support of lactulose.92 In
some centers, lactitol is preferred to lactulose, based on
small meta-analyses of even smaller trials.93,94
In populations with a high prevalence of lactose
intolerance, the use of lactose has been suggested.95
However, the only trial to show that stool-acidifying
enemas (lactose and lactulose) were superior to tapwater enemas was underpowered.96 The use of polyethylene glycol preparation97 needs further validation.
The dosing of lactulose should be initiated98 when
the three first elements of the four-pronged approach
are completed, with 25 mL of lactulose syrup every 12 hours until at least two soft or loose bowel movements per day are produced. Subsequently, the dosing
is titrated to maintain two to three bowel movements
per day. This dose reduction should be implemented.
It is a misconception that lack of effect of smaller
amounts of lactulose is remedied by much larger doses.
There is a danger for overuse of lactulose leading to
complications, such as aspiration, dehydration, hypernatremia, and severe perianal skin irritation, and overuse can even precipitate HE.99
Rifaximin. Rifaximin has been used for the therapy
of HE in a number of trials100 comparing it with placebo, other antibiotics, nonabsorbable disaccharides,
and in dose-ranging studies. These trials showed effect
of rifaximin that was equivalent or superior to the compared agents with good tolerability. Long-term cyclical
therapy over 3-6 months with rifaximin for patients
with OHE has also been studied in three trials (two
compared to nonabsorbable disaccharides and one
against neomycin) showing equivalence in cognitive
improvement and ammonia lowering. A multinational
study101 with patients having two earlier OHE bouts to
maintain remission showed the superiority of rifaximin
versus placebo (in the background of 91% lactulose
use). No solid data support the use of rifaximin alone.
Other Therapies. Many drugs have been used for
treatment of HE, but data to support their use are
limited, preliminary, or lacking. However, most of
these drugs can safely be used despite their limited
proven efficacy.
BCAAs. An updated meta-analysis of eight
randomized, controlled trials (RCTs) indicated that
oral BCAA-enriched formulations improve the manifestations of episodic HE whether OHE or
MHE.102,130 There is no effect of IV BCAA on the
episodic bout of HE.127
Metabolic Ammonia Scavengers. These agents,
through their metabolism, act as urea surrogates
excreted in urine. Such drugs have been used for treatment of inborn errors of the urea cycle for many years.
Different forms are available and currently present as
promising investigational agents. Ornithine phenylacetate has been studied for HE, but further clinical
reports are awaited.103 Glyceryl phenylbutyrate (GPB)
was tested in a recent RCT104 on patients who had
HEPATOLOGY, August 2014
experienced two or more episodes of HE in the last 6
months and who were maintained on standard therapy
(lactulose 6 rifaximin). The GPB arm experienced
fewer episodes of HE and hospitalizations as well as
longer time to first event. More clinical studies on the
same principle are under way and, if confirmed, may
lead to clinical recommendations.
L-ornithine L-aspartate (LOLA). An RCT on
patients with persistent HE demonstrated improvement by IV LOLA in psychometric testing and postprandial
supplementation with LOLA is ineffective.
Probiotics. A recent, open-label study of either lactulose, probiotics, or no therapy in patients with cirrhosis who recovered from HE found fewer episodes
of HE in the lactulose or probiotic arms, compared to
placebo, but were not different between either interventions. There was no difference in rates of readmission in any of the arms of the study.106
Glutaminase Inhibitors. Portosystemic shunting
up-regulates the intestinal glutaminase gene so that intestinal glutaminase inhibitors may be useful by reducing
the amounts of ammonia produced by the gut.
Neomycin. This antibiotic still has its advocates
and was widely used in the past for HE treatment; it
is a known glutaminase inhibitor.107
Metronidazole. As short-term therapy,108 metronidazole also has advocates for its use. However, longterm ototoxicity, nephrotoxicity, and neurotoxicity make
these agents unattractive for continuous long-term use.
Flumazenil. This drug is not frequently used. It
transiently improves mental status in OHE without
improvement on recovery or survival. The effect may be
of importance in marginal situations to avoid assisted
ventilation. Likewise, the effect may be helpful in difficult differential diagnostic situations by confirming
reversibility (e.g., when standard therapy unexpectedly
fails or when benzodiazepine toxicity is suspected).
Laxatives. Simple laxatives alone do not have the
prebiotic properties of disaccharides, and no publications have been forthcoming on this issue.
Albumin. A recent RCT on OHE patients on
rifaximin given daily IV albumin or saline showed no
effect on resolution of HE, but was related to better
postdischarge survival.109
18. Identify and treat precipitating factors for HE
(GRADE II-2, A, 1).
19. Lactulose is the first choice for treatment of
episodic OHE (GRADE II-1, B, 1).
HEPATOLOGY, Vol. 60, No. 2, 2014
20. Rifaximin is an effective add-on therapy to
lactulose for prevention of OHE recurrence (GRADE
I, A, 1).
21. Oral BCAAs can be used as an alternative or
additional agent to treat patients nonresponsive to
conventional therapy (GRADE I, B, 2).
22. IV LOLA can be used as an alternative or
additional agent to treat patients nonresponsive to
conventional therapy (GRADE I, B, 2).
23. Neomycin is an alternative choice for treatment of OHE (GRADE II-1, B, 2).
24. Metronidazole is an alternative choice for
treatment of OHE (GRADE II-3, B, 2).
Prevention of Overt Hepatic Encephalopathy
After an Episode of OHE. There are no randomized, placebo-controlled trials of lactulose for maintenance of remission from OHE. However, it is still
widely recommended and practiced. A single-center,
open-label RCT of lactulose demonstrated less recurrence of HE in patients with cirrhosis.33 A recent
RCT supports lactulose as prevention of HE subsequent to upper gastrointestinal (GI) bleeding.110
Rifaximin added to lactulose is the best-documented
agent to maintain remission in patients who have
already experienced one or more bouts of OHE while
on lactulose treatment after their initial episode of
Hepatic Encephalopathy After TIPS. Once TIPS
was popularized to treat complications of PH, its tendency to cause the appearance of HE, or less commonly,
intractable persistent HE, was noted. Faced with severe
HE as a complication of a TIPS procedure, physicians
had a major dilemma. Initially, it was routine to use
standard HE treatment to prevent post-TIPS HE.
However, one study illustrated that neither rifaximin
nor lactulose prevented post-TIPS HE any better than
placebo.111 Careful case selection has reduced the incidence of severe HE post-TIPS. If it occurs, shunt
diameter reduction can reverse HE.112 However, the
original cause for placing TIPS may reappear.
Another important issue with TIPS relates to the
desired portal pressure (PP) attained after placement of
stents. Too low a pressure because of large stent diameter can lead to intractable HE, as noted above. There
is a lack of consensus on whether to aim to reduce PP
by 50% or below 12 mmHg. The latter is associated
with more bouts of encephalopathy.113 It is widely
used to treat post-TIPS recurrent HE as with other
cases of recurrent HE, including the cases that cannot
be managed by reduction of shunt diameter.
Hepatic Encephalopathy Secondary to Portosystemic Shunts (PSSs). Recurrent bouts of overt HE in
patients with preserved liver function consideration
should lead to a search for large spontaneous PSSs.
Certain types of shunts, such as splenorenal shunts,
can be successfully embolized with rapid clearance of
overt HE in a fraction of patients in a good liver function status, despite the risk for subsequent VB.114
25. Lactulose is recommended for prevention of
recurrent episodes of HE after the initial episode
(GRADE II-1, A, 1).
26. Rifaximin as an add-on to lactulose is recommended for prevention of recurrent episodes of HE
after the second episode (GRADE I, A, 1).
27. Routine prophylactic therapy (lactulose or
rifaximin) is not recommended for the prevention of
post-TIPS HE (GRADE III, B, 1).
Discontinuation of Prophylactic Therapy. There
is a nearly uniform policy to continue treatment indefinitely after it has successfully reversed a bout of
OHE. The concept may be that once the thresholds
for OHE is reached, then patients are at high risk for
recurrent episodes. This risk appears to worsen as liver
function deteriorates. However, what often occurs are
recurrent bouts of OHE from a well-known list of precipitating factors. If a recurrent precipitating factor can
be controlled, such as recurrent infections or variceal
hemorrhages, then HE recurrence may not be a risk
and HE therapy can be discontinued. Even more influential on the risk for further bouts of OHE is overall
liver function and body habitus. If patients recover a
significant amount of liver function and muscle mass
from the time they had bouts of OHE, they may well
be able to stop standard HE therapy. There are very
little data on this issue, but tests positive for MHE or
CHE before stopping HE drug therapy will predict
patients at risk for recurrent HE.
28. Under circumstances where the precipitating
factors have been well controlled (i.e., infections and
VB) or liver function or nutritional status improved,
prophylactic therapy may be discontinued (GRADE
III, C, 2).
Treatment of Minimal HE and Covert HE
Although it is not standard to offer therapy for
MHE and CHE, studies have been performed using
several modes of therapy. The majority of studies have
been for less than 6 months and do not reflect the
overall course of the condition. Trials span the gamut
from small open-label trials to larger, randomized, controlled studies using treatments varying from probiotics, lactulose, and rifaximin. Most studies have shown
an improvement in the underlying cognitive status,
but the mode of diagnosis has varied considerably
among studies. A minority of studies used clinically
relevant endpoints. It was shown, in an open-label
study,115 that lactulose can prevent development of the
first episode of OHE, but the study needs to be replicated in a larger study in a blinded fashion before firm
recommendations can be made. Studies using lactulose
and rifaximin have shown improvement in quality of
life34,116 and also in driving simulator performance.117
Probiotics have also been used, but the open-label
nature, varying amounts and types of organisms, and
different outcomes make them difficult to recommend
as therapeutic options at this time.118-121
Because of the multiple methods used to define MHE
and CHE, varying endpoints, short-term treatment trials,
and differing agents used in trials to date, routine treatment for MHE is not recommended at this stage.
Exceptions could be made on a case-by-case basis using
treatments that are approved for OHE, particularly for
patients with CHE and West Haven Grade I HE.
29. Treatment of MHE and CHE is not routinely
recommended apart from a case-by-case basis
(GRADE II-2, B, 1).
Modulation of nitrogen metabolism is crucial to the
management of all grades of HE, and nutritional
options are relevant. Detailed recent guidelines for
nutrition of patients with HE are given elsewhere.122
Malnutrition is often underdiagnosed, and approximately 75% of patients with HE suffer from moderateto-severe protein-calorie malnutrition with loss of muscle mass and energy depots. Chronic protein restriction
is detrimental because patients’ protein requirements are
relatively greater than that of healthy patients and they
are at risk of accelerated fasting metabolism. Malnutrition and loss of muscle bulk is a risk factor for development of HE and other cirrhosis complications.
Sarcopenia has been proven to be an important negative
prognostic indicator in patients with cirrhosis.123,124 All
HE patients should undergo an assessment of nutritional status by taking a good dietary history, with
HEPATOLOGY, August 2014
anthropometric data and muscle strength measurement
as practical, useful measures of nutritional status. In the
undressed patient, particular attention is paid to the
muscle structures around the shoulders and gluteal
muscles. Pitfalls are water retention and obesity.
Although body mass index is rarely helpful, the heightcreatinine ratio may be useful, as well as the bioimpedance technique. More advanced techniques, such as
dual-energy X-ray absorptiometry/CT/MR, are rarely
useful for clinical purposes. The patient should undergo
a structured dietary assessment, preferably by a dietician,
or other specially trained staff. The majority of HE
patients will fulfill criteria for nutritional therapy. The
therapy is refeeding by moderate hyperalimentation, as
indicated below. Small meals evenly distributed
throughout the day and a late-night snack125 should be
encouraged, with avoidance of fasting. Glucose may be
the most readily available calorie source, but should not
be utilized as the only nutrition. Hyperalimentation
should be given orally to patients that can cooperate, by
gastric tube to patients who cannot take the required
amount, and parenterally to other patients. The nutrition therapy should be initiated without delay and
monitored during maintenance visits. The use of a multivitamin is generally recommended, although there are
no firm data on the benefits of vitamin and mineral
supplementation. Specific micronutrient replacement is
given if there are confirmed measured losses, and zinc
supplementation is considered when treating HE. If
Wernicke’s is suspected, large doses of thiamine should
be given parenterally and before any glucose administration. Administration of large amounts of nonsaline fluids should be adjusted so as to avoid induction of
hyponatremia, particularly in patients with advanced
cirrhosis. If severe hyponatremia is corrected, this
should be done slowly.
There is consensus that low-protein nutrition should
be avoided for patients with HE. Some degree of protein restriction may be inevitable in the first few days
of OHE treatment, but should not be prolonged. Substitution of milk-based or vegetable protein or supplementing with BCAAs is preferable to reduction of
total protein intake. Oral BCAA-enriched nutritional
formulation may be used to treat HE and generally
improves the nutritional status of patients with cirrhosis,126 but IV BCAA for an episode of HE has no
effect.127 The studies on the effect of oral BCAA have
been more encouraging128,129 and confirmed by a
recent meta-analysis of 11 trials.130 Ultimately, the
effects of these amino acids may turn out to have
more important effects on promotion of maintenance
of lean body mass than a direct effect on HE.
HEPATOLOGY, Vol. 60, No. 2, 2014
30. Daily energy intakes should be 35-40 kcal/kg
ideal body weight (GRADE I, A, 1).
31. Daily protein intake should be 1.2-1.5 g/kg/
day (GRADE I, A, 1).
32. Small meals or liquid nutritional supplements
evenly distributed throughout the day and a latenight snack should be offered (GRADE I, A, 1).
33. Oral BCAA supplementation may allow recommended nitrogen intake to be achieved and maintained in patients intolerant of dietary protein
(GRADE II-2, B, 2).
Liver Transplantation (LT)
Liver transplantation remains the only treatment
option for HE that does not improve on any other
treatment, but is not without its risks. The management
of these potential transplant candidates as practiced in
the United States has been published elsewhere,131,132
and European guidelines are under way. Hepatic encephalopathy by itself is not considered an indication for
LT unless associated with poor liver function. However,
cases do occur where HE severely compromises the
patient’s quality of life and cannot be improved despite
maximal medical therapy and who may be LT candidates despite otherwise good liver status. Large PSSs
may cause neurological disturbances and persistent HE,
even after LT. Therefore, shunts should be identified
and embolization considered before or during transplantation.133 Also, during the transplant workup, severe
hyponatremia should be corrected slowly.
Hepatic encephalopathy should improve after transplant, whereas neurodegenerative disorders will worsen.
Therefore, it is important to distinguish HE from
other causes of mental impairment, such as Alzheimer’s
disease and small-vessel cerebrovascular disease. Magnetic resonance imaging and spectroscopy of the brain
should be conducted, and the patient should be evaluated by an expert in neuropsychology and neurodegenerative diseases.134 The patient, caregivers, and
health professionals should be aware that transplantation may induce brain function impairment and that
not all manifestations of HE are fully reversible by
One difficult and not uncommon problem is the
development of a confusional syndrome in the postoperative period. The search of the cause is often difficult,
and the problem may have multiple origins. Patients
with alcoholic liver disease (ALD) and those with recurrent HE before transplantation are at higher risk. Toxic
effects of immunosuppressant drugs are a frequent
cause, usually associated with tremor and elevated levels
in blood. Other adverse cerebral effects of drugs may be
difficult to diagnose. Confusion associated with fever
requires a diligent, systematic search for bacterial or
viral causes (e.g., cytomegalovirus). Multiple causative
factors are not unusual, and the patient’s problem
should be approached from a broad clinical view.136
Economic/Cost Implications
As outlined under epidemiology, the burden of HE
is rapidly increasing and more cases of HE will be
encountered, with substantial direct costs being
attributed to hospitalizations for HE and to indirect
costs. The patients with HE hospitalized in the
United States in 2003 generated charges of approximately US$ 1 billion.40,137 Resource utilization for
this group of patients is also increasing as a result of
longer lengths of stay and more complex and expensive hospital efforts, as well as a reported in-patient
mortality of 15%. There are no directly comparable
EU cost data, but by inference from epidemiological
data, the event rate should be approximately the same
and the costs comparable, differences between U.S.
and EU hospital financing notwithstanding. These
costs are an underestimate, because out-patient care,
disability and lost productivity, and the negative
effect on the patient’s family or support network were
not quantified.138
The cost of medications is very variable to include in
analyses because it varies widely from country to country and are usually determined by what the pharmaceutical companies believe the market can sustain.
Regarding the beneficial effects of rifaximin, costeffective analyses based on current drug prices favor
treatments that are lactulose based,92,139 as do analyses
of accidents, deaths/morbidity, and time off from
work73 in patients with MHE or CHE. Therefore, until
the costs of other medications fall, lactulose continues
to be the least expensive, most cost-effective treatment.
Alternative Causes of Altered Mental Status
Disorders to Be Considered
The neurological manifestations of HE are nonspecific. Therefore, concomitant disorders have to be considered as an additional source of central nervous
system dysfunction in any patient with CLD. Most
important are renal dysfunction, hyponatremia, diabetes mellitus (DM), sepsis, and thiamine deficiency
(Wernicke’s encephalopathy); noteworthy also is intracranial bleeding (chronic subdural hematoma and
parenchymal bleeding).
Interaction Between Concomitant Disorders and
Liver Disease With Regard to Brain Function
Hyponatremia is an independent risk factor for
development of HE in patients with cirrhosis.140,141
The incidence of HE increases142 and the response
rate to lactulose therapy decreases143 with decreasing
serum sodium concentrations.
Diabetes mellitus has been suggested as a risk factor
for development of HE, especially in patients with hepatitis C virus (HCV) cirrhosis,144 but the relationship
may also be observed in other cirrhosis etiologies.145
An increased risk to develop HE has also been
shown in patients with cirrhosis with renal dysfunction,146 independent of the severity of cirrhosis.
Neurological symptoms are observed in 21%-33%
of patients with cirrhosis with sepsis and in 60%-68%
of those with septic shock.147 Patients with cirrhosis
do not differ from patients without cirrhosis regarding
their risk to develop brain dysfunction with sepsis,148
although it is assumed that systemic inflammation and
hyperammonemia act synergistically with regard to the
development of HE.
Thiamine deficiency predominantly occurs in
patients with ALD, but may also occur as a consequence of malnutrition in end-stage cirrhosis of any
cause. The cerebral symptoms disorientation, alteration
of consciousness, ataxia, and dysarthria cannot be differentiated as being the result of thiamine deficiency or
hyperammonemia by clinical examination.149 In any
case of doubt, thiamine should be given IV before
glucose-containing solutions.
Effect of the Etiology of the Liver Disease Upon
Brain Function
Data upon the effect of the underlying liver disease
on brain function are sparse, except for alcoholism and
hepatitis C. Rare, but difficult, cases may be the result
of Wilson’s disease.
Even patients with alcohol disorder and no clinical
disease have been shown to exhibit deficits in episodic
memory,150 working memory and executive functions,151 visuoconstruction abilities,152 and upper- and
lower-limb motor skills.153 The cognitive dysfunction
is more pronounced in those patients with alcohol disorder who are at risk of Wernicke’s encephalopathy as
a result of malnutrition or already show signs of the
problem.154 Thus, it remains unclear whether the disturbance of brain function in patients with ALD is the
result of HE, alcohol toxicity, or thiamine deficiency.
There is mounting evidence that HCV is present
and replicates within the brain.155-158 Approximately
HEPATOLOGY, August 2014
half of HCV patients suffer chronic fatigue irrespective
of the grade of their liver disease,159,160 and even
patients with only mild liver disease display cognitive
dysfunction,161,162 involving verbal learning, attention,
executive function, and memory. Likewise, patients
with primary biliary cirrhosis and primary sclerosing
cholangitis may have severe fatigue and impairment of
attention, concentration, and psychomotor function
irrespective of the grade of liver disease.163-168
Diagnostic Measures to Differentiate Between HE
and Cerebral Dysfunction Resulting From Other
Because HE shares symptoms with all concomitant
disorders and underlying diseases, it is difficult in the
individual case to differentiate between the effects of
HE and those resulting from other causes. In some
cases, the time course and response to therapy may
be the best support of HE. As mentioned, a normal
blood ammonia level in a patient suspected of HE
calls for consideration. None of the diagnostic measures used at present has been evaluated for their ability to differentiate between HE and other causes of
brain dysfunction. The EEG would not be altered by
DM or alcohol disorders, but may show changes similar to those with HE in cases of renal dysfunction,
hyponatremia, or septic encephalopathy. Psychometric
tests are able to detect functional deficits, but are
unable to differentiate between different causes for
these deficits. Brain imaging methods have been evaluated for their use in diagnosing HE, but the results
are disappointing. Nevertheless, brain imaging should
be done in every patient with CLD and unexplained
alteration of brain function to exclude structural
lesions. In rare cases, reversibility by flumazenil may
be useful.
After a hospital admission for HE, the following
issues should be addressed.
Discharge From Hospital
1. The medical team should confirm the neurological
status before discharge and judge to what extent
the patient’s neurological deficits could be attributable to HE, or to other neurological comorbidities,
for appropriate discharge planning. They should
inform caregivers that the neurological status may
change once the acute illness has settled and that
requirement for medication could change.
HEPATOLOGY, Vol. 60, No. 2, 2014
2. Precipitating and risk factors for development of
HE should be recognized. Future clinical management should be planned according to (1) potential
for improvement of liver function (e.g., acute alcoholic hepatitis, autoimmune hepatitis, and hepatitis
B), (2) presence of large portosystemic shunts
(which may be suitable for occlusion), and (3)
characteristics of precipitating factors (e.g., prevention of infection, avoidance of recurrent GI bleeding, diuretics, or constipation).
3. Out-patient postdischarge consultations should be
planned to adjust treatment and prevent the reappearance of precipitating factors. Close liaison
should be made with the patient’s family, the general practitioner, and other caregivers in the primary health service, so that all parties involved
understand how to manage HE in the specific
patient and prevent repeated hospitalizations.
and may include their relatives. All these issues
should be incorporated into the follow-up plan.
5. Treatment endpoints depend on the monitoring used
and the specialist clinic, but at least they have to cover
two aspects: (1) cognitive performance (improvement
in one accepted test as a minimum) and (2) daily life
autonomy (basic and operational abilities).
6. Nutritional aspects: weight loss with sarcopenia
may worsen HE, and, accordingly, the nutritional
priority is to provide enough protein and energy to
favor a positive nitrogen balance and increase in
muscle mass, as recommended above.
7. Portosystemic shunt: occlusion of a dominant shunt
may improve HE in patients with recurring HE
and good liver function.114 Because the current
experience is limited, the risks and benefits must be
weighed before employing this strategy.
Suggestions for Future Research
Preventive Care After Discharge
1. Education of patients and relatives should include (1)
effects of medication (lactulose, rifaximin, and so on)
and the potential side effects (e.g., diarrhea), (2) importance of adherence, (3) early signs of recurring HE,
and (4) actions to be taken if recurrence (e.g., anticonstipation measures for mild recurrence and referral to
general practitioner or hospital if HE with fever).
2. Prevention of recurrence: the underlying liver
pathology may improve with time, nutrition, or
specific measures, but usually patients who have
developed OHE have advanced liver failure without
much hope for functional improvements and are
often potential LT candidates. Managing the complications of cirrhosis (e.g., spontaneous bacterial
peritonitis and GI bleeding) should be instituted
according to available guidelines. Pharmacological
secondary prevention is mentioned above.
3. Monitoring neurological manifestations is necessary
in patients with persisting HE to adjust treatment
and in patients with previous HE to investigate the
presence and degree of MHE or CHE or signs of
recurring HE. The cognitive assessment depends
on the available normative data and local resources.
The motor assessment should include evaluation of
gait and walking and consider the risk of falls.
4. The socioeconomic implications of persisting HE or
MHE or CHE may be very profound. They include
a decline in work performance, impairment in quality of life, and increase in the risk of accidents.
These patients often require economic support and
extensive care from the public social support system
This section deals with research into the management of HE. However, such research should always be
based on research into the pathophysiology of HE. It
is necessary to gain more insight into which liver functions are responsible for maintenance of cerebral functions, which alterations in intestinal function and
microbiota make failure of these liver functions critical, which brain functions are particularly vulnerable
to the combined effects of the aforementioned events,
and, finally, which factors outside this axis that result
in the emergence of HE (e.g., inflammation, endocrine
settings, or malnutrition). Therefore, the research fields
into pathophysiology and clinical management should
remain in close contact. Such collaboration should
result in new causal and symptomatic treatment
modalities that need and motivate clinical trials.
There is a severe and unmet need for controlled
clinical trials on treatment effects on all the different
forms of HE. Decisive clinical studies are few,
although the number of patients and their resource
utilization is high. There are no data on which factors
and patients represent the higher costs, and research
is needed to examine the effect of specific cirrhosisrelated complications. At present, there is an insufficient basis for allocating resources and establishing
priority policies regarding management of HE. Many
drugs that were assessed for HE several decades ago
were studied following a standard of care that, at
present, is obsolete. Any study of treatment for HE
should be reassessed or repeated using the current
standard of care. It is critical to develop protocols to
identify precipitating factors and ACLF. The benefit
HEPATOLOGY, August 2014
Table 7. Suggested Areas of Future Research in HE
Effect on individuals
and society
Demonstrate the effects of HE on patients
and society in order to encourage
diagnosis and therapy
1. Studies on economic and social burden among different societies
2. Studies on cultural aspects on therapy and compliance with treatment
3. Long-term natural history studies
Diagnostic improvement
Enhance the diagnostic accuracy
1. Studies on clinically applicable high-sensitivity screening tests that can guide
which patients may benefit from dedicated testing
2. Development of algorithms to decide when and how to apply the diagnostic
3. Studies on competing factors (i.e., HCV, delirium, depression, and narcotic
use on diagnosis)
4. Studies on biomarkers for presence and progression of neurological
Treatment goals
Improve the appropriate use of therapeutic
tools in different clinical scenarios
1. Studies on selecting who will benefit from preventing the first OHE episode
2. Studies for >6 months to evaluate compliance and continued effects on
cognitive improvement
3. Develop protocols focused on how to diagnose and treat precipitating factors
4. Determine what should be the standard protocol to investigate new therapies
5. Decide which therapies have been adequately studied and are not a priority
for additional studies
of recently assessed drugs is concentrated in the prevention of recurrence, and there is a large need for
trials on episodic HE.
There is also an unmet need for research into diagnostic methods that is necessary to form a basis for
clinical trials. The diagnosis of MHE and CHE has
received enormous interest, but it is still not possible
to compare results among studies and the precision
should be improved. It may be useful to develop, validate, and implement HE scales that combine the
degree of functional liver failure and PSS with more
than one psychometric method.
One important area of uncertainty is whether the
term CHE, which was introduced to expand MHE
toward grade I of oriented patients, is informative and
clinically valuable. This needs to be evaluated by a
data-driven approach. Likewise, the distinction
between isolated liver failure and ACLF-associated HE
should be evaluated by independent data.
A closer scientific collaboration between clinical
hepatologists and dedicated brain researchers, including functional brain imaging experts, is needed. Likewise, neuropsychologists and psychiatrists are needed
to clarify the broad spectrum of neuropsychiatric
symptoms that can be observed in patients with liver
disease. Syndrome diagnoses should be more precisely
classified and transformed into classifiable entities
based on pathophysiology and responding to the
requirements of clinical hepatology practice and
Future studies should fill our gaps in knowledge.
They should be focused on assessing the effects of HE
on individuals and society, how to use diagnostic tools
appropriately, and define the therapeutic goals in each
clinical scenario (Table 7).
Recommendations on Future Research in HE
The existing literature suffers from a lack of standardization, and this heterogeneity makes pooling of
data difficult or meaningless. Recommendations to
promote consistency across the field have been published by ISHEN.66 Following is a synopsis of the
Trials in Patients With Episodic OHE
1. Patients who are not expected to survive the hospitalization, who are terminally ill or have ACLF
should be excluded.
2. A detailed standard-of-care algorithm must be
agreed upon a priori and must be instituted and
monitored diligently throughout the trial.
3. Patients should not be entered into trials until after
the institution of optimal standard-of-care therapy
and only if their mental state abnormalities persist.
4. Provided the optimal standard of care is instituted
and maintained, the treatment trial can be initiated
earlier if they include a placebo comparator; this
would allow an evaluation of the trial treatment as
an adjuvant to standard therapy.
5. Large-scale, multicenter treatment trials should be
evaluated using robust clinical outcomes, such as
in-hospital and remote survival, liver-related and
total deaths, completeness and speed of recovery
HEPATOLOGY, Vol. 60, No. 2, 2014
from HE, number of days in intensive care, total
length of hospital stay, quality-of-life measures, and
associated costs. Markers for HE, such as psychometric testing, can be employed if standardized and
validated tools are available in all centers. Individual centers can utilize additional, accessible, validated markers if they choose.
6. Proof-of-concept trials will additionally be monitored using tools that best relate to the endpoints
anticipated or expected; this may involve use of neural imaging or measurement of specific biomarkers.
Trials in Patients With MHE or CHE
Trials in this population should be randomized and
placebo controlled.
1. Patients receiving treatment for OHE or those with
previous episodes of OHE should be excluded.
2. In single-center or proof-of-concept studies, investigators may use tests for assessing the severity of HE
with which they are familiar, provided that normative reference data are available and the tests have
been validated for use in this patient population.
3. Further information is needed on the interchangeability and standardization of tests to assess the
severity of HE for use in multicenter trials. As an
interim, two or more of the current validated tests
should be used and applied uniformly across
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